content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.observable.internal.operators;
  
  import java.util.concurrent.Callable;
  import java.util.concurrent.atomic.AtomicReference;
  
  import io.reactivex.common.*;
  import io.reactivex.common.exceptions.*;
  import io.reactivex.common.functions.*;
  import io.reactivex.common.internal.disposables.DisposableHelper;
  import io.reactivex.common.internal.functions.ObjectHelper;
  import io.reactivex.observable.*;
  import io.reactivex.observable.internal.disposables.EmptyDisposable;
  
  /**
   * Creates a resource and a dependent Maybe for each incoming Observer and optionally
   * disposes the resource eagerly (before the terminal event is send out).
   *
   * @param <T> the value type
   * @param <D> the resource type
   */
  public final class MaybeUsing<T, D> extends Maybe<T> {
  
      final Callable<? extends D> resourceSupplier;
  
      final Function<? super D, ? extends MaybeSource<? extends T>> sourceSupplier;
  
      final Consumer<? super D> resourceDisposer;
  
      final boolean eager;
  
      public MaybeUsing(Callable<? extends D> resourceSupplier,
              Function<? super D, ? extends MaybeSource<? extends T>> sourceSupplier,
              Consumer<? super D> resourceDisposer,
              boolean eager) {
          this.resourceSupplier = resourceSupplier;
          this.sourceSupplier = sourceSupplier;
          this.resourceDisposer = resourceDisposer;
          this.eager = eager;
      }
  
      @Override
      protected void subscribeActual(MaybeObserver<? super T> observer) {
          D resource;
  
          try {
              resource = resourceSupplier.call();
          } catch (Throwable ex) {
              Exceptions.throwIfFatal(ex);
              EmptyDisposable.error(ex, observer);
              return;
          }
  
          MaybeSource<? extends T> source;
  
          try {
              source = ObjectHelper.requireNonNull(sourceSupplier.apply(resource), "The sourceSupplier returned a null MaybeSource");
          } catch (Throwable ex) {
              Exceptions.throwIfFatal(ex);
              if (eager) {
                  try {
                      resourceDisposer.accept(resource);
                  } catch (Throwable exc) {
                      Exceptions.throwIfFatal(exc);
                      EmptyDisposable.error(new CompositeException(ex, exc), observer);
                      return;
                  }
              }
  
              EmptyDisposable.error(ex, observer);
  
              if (!eager) {
                  try {
                      resourceDisposer.accept(resource);
                  } catch (Throwable exc) {
                      Exceptions.throwIfFatal(exc);
                      RxJavaCommonPlugins.onError(exc);
                  }
              }
              return;
          }
  
          source.subscribe(new UsingObserver<T, D>(observer, resource, resourceDisposer, eager));
      }
  
      static final class UsingObserver<T, D>
      extends AtomicReference<Object>
      implements MaybeObserver<T>, Disposable {
  
  
          private static final long serialVersionUID = -674404550052917487L;
  
          final MaybeObserver<? super T> actual;
  
          final Consumer<? super D> disposer;
  
          final boolean eager;
  
          Disposable d;
  
          UsingObserver(MaybeObserver<? super T> actual, D resource, Consumer<? super D> disposer, boolean eager) {
              super(resource);
              this.actual = actual;
              this.disposer = disposer;
              this.eager = eager;
          }
  
          @Override
          public void dispose() {
              d.dispose();
              d = DisposableHelper.DISPOSED;
              disposeResourceAfter();
          }
  
          @SuppressWarnings("unchecked")
          void disposeResourceAfter() {
              Object resource = getAndSet(this);
              if (resource != this) {
                  try {
                      disposer.accept((D)resource);
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      RxJavaCommonPlugins.onError(ex);
                  }
              }
          }
  
          @Override
          public boolean isDisposed() {
              return d.isDisposed();
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              if (DisposableHelper.validate(this.d, d)) {
                  this.d = d;
  
                  actual.onSubscribe(this);
              }
          }
  
          @SuppressWarnings("unchecked")
          @Override
          public void onSuccess(T value) {
              d = DisposableHelper.DISPOSED;
              if (eager) {
                  Object resource = getAndSet(this);
                  if (resource != this) {
                      try {
                          disposer.accept((D)resource);
                      } catch (Throwable ex) {
                          Exceptions.throwIfFatal(ex);
                          actual.onError(ex);
                          return;
                      }
                  } else {
                      return;
                  }
              }
  
              actual.onSuccess(value);
  
              if (!eager) {
                  disposeResourceAfter();
              }
          }
  
          @SuppressWarnings("unchecked")
          @Override
          public void onError(Throwable e) {
              d = DisposableHelper.DISPOSED;
              if (eager) {
                  Object resource = getAndSet(this);
                  if (resource != this) {
                      try {
                          disposer.accept((D)resource);
                      } catch (Throwable ex) {
                          Exceptions.throwIfFatal(ex);
                          e = new CompositeException(e, ex);
                      }
                  } else {
                      return;
                  }
              }
  
              actual.onError(e);
  
              if (!eager) {
                  disposeResourceAfter();
              }
          }
  
          @SuppressWarnings("unchecked")
          @Override
          public void onComplete() {
              d = DisposableHelper.DISPOSED;
              if (eager) {
                  Object resource = getAndSet(this);
                  if (resource != this) {
                      try {
                          disposer.accept((D)resource);
                      } catch (Throwable ex) {
                          Exceptions.throwIfFatal(ex);
                          actual.onError(ex);
                          return;
                      }
                  } else {
                      return;
                  }
              }
  
              actual.onComplete();
  
              if (!eager) {
                  disposeResourceAfter();
              }
          }
      }
  }
  